ElasticSearch Quality Control & Assurance 4

Question 1

What is the correct way to verify that an Elasticsearch snapshot completed successfully and the data is restorable?

Accepted Answer

Check that _cat/snapshots shows status=SUCCESS and perform a test restore to a separate index

Answer

Verifying snapshot integrity requires both a SUCCESS status and an actual test restore, since file-level corruption won't be detected by status alone.

Question 2

Which circuit breaker in Elasticsearch is specifically designed to prevent field data loading from exhausting heap memory?

Accepted Answer

Fielddata circuit breaker

Answer

The fielddata circuit breaker limits the amount of heap used by loading field data into memory, preventing out-of-memory errors from large aggregation or sorting operations.

Question 3

During a quality review, you notice search latency spikes every 30 seconds. What default Elasticsearch behavior is most likely causing this?

Accepted Answer

Index refresh interval creating a new segment

Answer

Elasticsearch's default refresh interval is 1 second, but periodic segment merges can cause latency spikes; a refresh interval set to 30s or segment merges happening at that cadence are common culprits.

Question 4

What does `index.number_of_replicas: 0` during a bulk reindex improve, and what quality risk does it introduce?

Accepted Answer

Improves indexing speed; risks data loss if a node fails during reindex

Answer

Removing replicas during reindex significantly improves throughput by eliminating replica writes, but if a node fails before replicas are restored, that shard's data is permanently lost.

Question 5

Which Elasticsearch cat API provides the fastest way to identify shards that are currently being initialized or relocating across nodes?

Accepted Answer

_cat/shards?v&h=index,shard,prirep,state,node

Answer

`_cat/shards` with the state column shows each shard's current status (STARTED, INITIALIZING, RELOCATING, UNASSIGNED), making it the quickest way to track shard movement.

ElasticSearch Practice Test

ElasticSearch Practice Test

ElasticSearch Quality Control & Assurance 4